Questions tagged [signature]

This tag should be used for questions regarding digital signatures. A digital signature proves that the owner of a private key produced or endorsed a given message. These are used in transactions to prove that an output can be spent in a transaction.

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How to calculate the public key, compute point P and create signature using ECDSA?

I'm quite new to the intricacies of bitcoin cryptography and ECDSA and elliptic curve cryptography has me quite stymied. I am faced with a curve with the equation: y^2 = x^3 + 7 of order N=39 with ...
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1 vote
1 answer
49 views

Cryptographic digital signatures

I have a doubt since the public keys are known to everyone, so someone could falsify a transaction by writing down a deposit from a public address to another public address in a new block and solving ...
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1 vote
1 answer
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Order of Signatures in Multisig-Scheme

3 Entities (A/B/C) create a collaborative Multisig Wallet (e.g. 2-of-3). A creates an unsigned TX and shares it with B/C. They (B/C) sign and broadcast. Looking at the TX on the network, can A make ...
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1 answer
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Standard library for schnorr signature algorithm

I am trying to create a blockchain demonstration to get used to the technology. The thing is: I want to use Schnorr signatures, but I can't seem to find a library for that, and I want to make sure ...
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1 vote
1 answer
21 views

Does signing a message as specified in AOPP incur a fee?

Does signing a message as specified in Address Ownership Proof Protocol (AOPP) incur a fee? I think not - there is nothing written in the specification about broadcasting anything to the Bitcoin ...
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0 votes
1 answer
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Is it Possible to Create Signature Chains for Private Keys to Sign Transactions with? Similar to how Certificate Authorities Use Intermediate Certs?

I am wondering if it is possible to implement this flow with bitcoin private keys, similar to how certificate authorities have a root cert and an intermediate cert used to sign csr's. It would be ...
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2 votes
1 answer
59 views

Bitcoin transaction inquiry

if suppose a someone offers a prize for anyone that can solve a specific challenge, how will the solver make sure that he/she collects the reward? Does the solver need to send the solution directly to ...
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3 votes
1 answer
85 views

What is the probability of an ECDSA signature being less than 71 bytes

Since DER requires R and s values being minimally encoded signed integers, they could be less than the expected 32 bytes. What is the probability that one or both of R and s are less than 32 bytes for ...
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1 vote
3 answers
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Why can't I modify someone else's transactions, if I have their signature data?

As I know, signature system is adding signature to end of transaction. And doesn’t hash transaction, so others can know my signature. If I can send a message directly to the node, can I use other’s ...
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0 votes
1 answer
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What is the relationship between r in signature and the public key

I've been reading about ECDSA in here. Step 11 says that you only need the ‘x‘ value (20 bytes) for the signature, and that value will be called ‘R‘ Does that say that R is the x-coordinate of the ...
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0 votes
1 answer
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How long is SIGHASH?

I am reading these two posts 1 2, and following step by step. I almost understand, but I still have some questions. Before signing, input script should be removed and replaced by pre locking script. ...
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1 vote
1 answer
55 views

How many times and where exactly is ECDSA used in Bitcoin?

I'm currently a little confused about where exactly ECDSA is used in the transaction process... some resources seem to say it's used once, whereas others seem to say it's used three times. Which is ...
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1 answer
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How to calculate R, S, and Z from raw bitcoin transaction with witness?

How can I calculate the R, S, and Z values from a raw bitcoin transaction? I can extract them with rscan.py, but that doesn't work for new transactions.
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5 votes
1 answer
389 views

What is signature grinding?

What is signature grinding and why does the answer to What is the size and weight of a wrapped segwit single-sig input? "highly recommend it"?
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-3 votes
4 answers
229 views

How to forge a signature with fixed Z value

I want to forge a signature with a fixed z value, what is the formula to do that
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5 votes
2 answers
292 views

What is an adaptor signature?

What is an adaptor signature in Bitcoin? A simple definition with some examples that could be understood without knowing cryptography in detail
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1 vote
1 answer
70 views

Curious about the Math that makes Bitcoin/Blockchain work ! Any good resources to learn it?

A bit of a background about me ; Computer Engineer but during my studies i didn't dive too deep into the maths , especially the maths that makes the blockchain and cryptography work looking for advice ...
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2 votes
1 answer
103 views

Meaning of "Drop the signature" comments in OP_CHECKSIG code (Bitcoin v0.1.0)

I'm doing my homework by reading the C++ code of the 0.1.0 release of Bitcoin available here. I'm interested in better understanding how to validate transaction 1 of block 170. This transaction has ...
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0 votes
0 answers
59 views

What is the best site/tool/way for finding the RSZ values of a bitcoin transaction? [duplicate]

The two most popular sites for doing this are down which are https://2coin.org/ and https://2xoin.com/getRSZfromRawTX/ with no indication they'll ever return to be usable. Can anyone here link any ...
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6 votes
1 answer
455 views

Why is it important that nonces when signing not be related?

I understand that if nonces (usually denoted k in the signature algorithm) are related signing with the same public key that this reveals information about the private key. I would like to get a ...
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2 votes
1 answer
42 views

Are there possible attack/failure scenarios when no new nodes verify old signatures anymore (keeping the assumevalid defaults)?

This question came up in a recent discussion with Hasu and I was wondering if there is a good/practical reason why a newly syncing node should change the assumevalid option to 0 (verifying all the ...
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-2 votes
1 answer
122 views

How to get bitcoin transaction nonce from transaction signature?

Subj. Looking for a code for calculate/get bitcoin transaction nonce. Help me please. ??? Thank you.
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0 votes
1 answer
38 views

how target walled address is secure to save received amount?

What about if I (as a hacker) change the amount from 5 to 1 for any transaction and put signature with my (as a hacker) Private Key and mine that block again. Yes, I lose 1 coin, At the same time isn'...
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0 votes
1 answer
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Why is signature S value is unnecessarily high not safe?

I get frequent warning when sending RawTX to PushTX message (Non-canonical signature: S value is unnecessarily high) Why is signature S with a large value dangerous (that is, when the first HEX ...
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0 votes
0 answers
53 views

Signing a transaction(Signature must be zero for failed CHECK(MULTI)SIG operation)

I try to sign raw transaction. Here is the instruction I used for it Redeeming a raw transaction step by step example required Python code I used to sign the transaction import hashlib import codecs ...
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1 vote
4 answers
103 views

If the nodes are what keep Bitcoin decentralized, what if some big internet company spun up 60%+ majority nodes?

If the nodes are what keep Bitcoin decentralized, what if some big internet company spun up 60%+ majority nodes? What’s stopping them from manipulating the blockchain to change transactions?
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1 vote
1 answer
80 views

What exactly is signed in "prev_out"?

What is signed by scriptSig? I use my private key to sign data from the unspent transaction? I sign the "prev_out" object? I read that the signature in "prev_out" is there to ...
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0 votes
2 answers
152 views

Signature doesn't prove that the owner of a Private Key produced a given message

Let's assume I am a developer of Bitcoin wallet. If I create a private key without implementing a seed phrase methodology (not using the principles of BIP32 and BIP39), is there at least the slightest ...
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1 vote
1 answer
55 views

How to get Y from X

Ok, so I get address generation now, and I understand that X is hashed, however for verification of a signature, we need the public point, (x,y) How would one get Y from X? Lets take an example, im ...
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0 votes
0 answers
36 views

Which elements of a P2PKH transaction are signed by default, and how is the signature used?

I'm working through the developer guide on bitcoin.org and there is a part of the section on transactions which isn't very clear. This diagram shows the elements of a transaction which are signed ...
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0 votes
0 answers
170 views

Transaction signing and security: Different signing approaches

I am currently studying for an exam and reviewing a past one from the CS 251: Bitcoin and Crypto Currencies course in Stanford with the following question on transaction signing. I have written my ...
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2 votes
0 answers
58 views

Why is adding s values in half aggregation insecure?

Jonas Nick an Tim Ruffing discussed in a presentation that summing up the s values in signature half aggregation would be insecure (without giving the reason) They presented a secure solution which ...
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3 votes
1 answer
142 views

Why is full blockwide signature aggregation of schnorr signatures non-interactive?

I can only think of the MuSig paper describing how Rouge attacks are prevented by also committing to the public key of all signers. But as far as I understand the case of multisig is not the same as ...
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4 votes
2 answers
233 views

Why does blockwide signature aggregation prevent adaptor signatures?

In a recent video about half signatures, Jonas Nick mentions that blockwide signature aggregation interferes with adaptor signatures and offering atomic swaps (I guess via PTLCs). I am confused about ...
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1 vote
1 answer
165 views

Creating Witness Signature: non-mandatory-script-verify-flag (Signature must be zero for failed CHECK(MULTI)SIG operation)

So I am trying to do my own witness signatures as described in bip143. I have code that correctly verifies the example signature, so I thought I had a hold of the basic signing and verification. I ...
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0 votes
1 answer
113 views

Is this a transaction?

I found an old wallet.dat but i dont know what is this. Is it a transaction that is not signed? If yes please help. I dont have a clue about cryptography. I have read and seen some tutorials but i ...
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2 votes
2 answers
105 views

The example signature in BIP143 doesn't validate?

In BIP143 the first example has a witness signature and it doesn't appear to validate/be correct?! I wrote a super simple python program to demonstrate import ecdsa import asn1 #Importing the 3 ...
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0 votes
1 answer
58 views

bip143 witness formatting

in bip143 thet define a witness signature. In the first example there is a witness broken down witness 00 02 ...
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1 vote
1 answer
95 views

What does bitcoin do that prevents someone from using your coins by just generating a key pair and saying "you" sent those coins?

I think I'm missing and understanding about the current process of how your wallet works and how the transactions are signed. For example, if I'm user "A" and there exists a transaction from ...
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0 votes
1 answer
48 views

What is the data structure of the signature cache in Bitcoin?

There is a signature cache in Bitcoin, which is used to cache the result of signature verification to avoid extra signature verification. What data is stored in the signature cache? Is it stored in ...
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-1 votes
1 answer
68 views

Orderly Transition Away from ECC? Or Bitcoin to zero?

Let's say asymmetric public key cryptography is wide open, and can be broken using a public key or the signature. Namely, that I can determine the private key using the information revealed in a ...
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1 vote
1 answer
57 views

Are high-s ECDSA signatures forbidden in segwit witnesses?

I must have looked that up five times by now, but did segwit actually forbid high-s ECDSA signatures in witnesses, esp. in standard single-sig constructions such as P2SH-P2WPKH or P2WPKH? Or are high-...
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0 votes
2 answers
458 views

How to prove wallet ownership? [duplicate]

Context I would like to verify being A has access to a wallet and hence would like to ask them to pay a minimum amount to a particular wallet address owned by someone other than me, e.g. ...
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3 votes
1 answer
143 views

Are UTXOs signed with a private key?

Are UTXOs signed by a private key? I'm trying to understand exactly which parts of Bitcoin use public and private keys. You need a private key in order to generate transaction output, and to create a ...
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4 votes
1 answer
309 views

Are Bitcoin's blocks signed by the miner?

To my understanding, at no point in the Bitcoin Whitepaper does it say that blocks are signed by the miner. However, one could see the advantage of having blocks signed. Thus I wonder if in the ...
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3 votes
1 answer
136 views

How to verify a lnurl-auth callback with python

I want to create a Python implementation of an lnurl-auth server. I started a quick HTTP server to be the callback url, and captured the signed callback sent by BLW on Android. ?tag=login &k1=...
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0 votes
0 answers
44 views

RPC to sign PSBT with private key

What is the PSBT related RPC which works similar to signrawtransactionwithkey ?
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0 votes
2 answers
413 views

Deleting Electrum wallet and setting up new one

I set up an Electrum wallet before I learnt that you should verify the signature. While I went straight to the electrum.org website to download it, I would still like to be secure, just in case. So I ...
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0 votes
0 answers
60 views

blockchain scanning

Hello friends please let me know that is there any script that can scan the entire blockchain and extract the signature values and find the match of given input. lets suppose i give the input "...
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0 votes
0 answers
16 views

How to create signature for the payload (data)using private key in java with bitcoinj? [duplicate]

I have private key as 'cUN9LNcEC54HAbWAwUs6coPSc72TcQYzxf4qSqdHJPVKSapeHzFj' and payload as 'hello', now how to create the signature for this payload using private key in java with bitcoinj library? ...
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